Metformin is widely used as a first-line medication for type 2 diabetes (T2D). Recent mouse models have shown that metformin increases the abundance of Akkermansia muciniphila (a strict anaerobe that exerts beneficial effects on glucose homeostasis), suggesting that its therapeutic effect may rely in the modulation of gut microbiota. In this double-blind randomised trial, patients with newly diagnosed T2D who were naive to treatment received either metformin (n=22) or placebo (n=18) for 4 months. In the metformin group, several alterations of microbiota were identified after the treatment including an increase of Escherichia and a decrease of Intestinibacter at the genus level. There...]]>